Greenlee 03607 Kwik Stepper Step Bit Kit, 2-Piece Cut up through 3/8-Inch mild steel, copper, brass, aluminum, wood, plastic and laminates Hole Size : From 1/8 IN (3.200 MM) through 1-3/8 IN (3.200 - 34.900 MM) Balanced, double-flute construction requires less pressure, does the work for you Made from hardened high-speed steel vs carbon steel for longer life Resists walking or skidding, even on round surfaces